The earth is approximately 12740 km in diameter. The totally arbitrary but commonly accepted definition of the "edge of space" is 100 km. For all practical purposes, that is vacuum, exvcept for a trace of air.There is, of couse, no hard, fast "top" of the atmosphere as there is a surface of the ocean. It very rapidly gets thinner as one goes up, but three quarters of the atmosphere's mass is below 11 km.

The important thing to remember is that the earth is primarily a ball of molten rock and metal, capped by a thin crust of stone, surrounded by just a whisper of gas and moisture, surrounded by an infinite vacuum. Everything that matters too us occurs in that thin layer.